User interface for spectrometer

ABSTRACT

A method for graphically forming a difference spectrum from a sample spectrum and a reference spectrum on a computer system includes displaying an initial difference spectrum on the display the initial difference spectrum being equal to the sample spectrum, selecting a data point in the initial difference spectrum, having an associated wave number, with a relative pointing device on the display, moving the data point a measurable amount on the display with the relative pointing device, determining a scaling factor in response to the measurable amount and to a data point in the reference spectrum having the same associated wave number, scaling each data point in the reference spectrum by the scaling factor to form a scaled reference spectrum, determining the difference spectrum between the sample spectrum and the scaled reference spectrum, and displaying at least a portion of the difference spectrum on the display.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention is a continuation-in-part of application Ser. No.08/333,955 filed Nov. 3, 1994, now U.S. Pat. No. 5,579,462.

BACKGROUND OF THE INVENTION

The present invention relates generally to graphical display of spectraldata, and more specifically to user interface enhancements thatfacilitate the examination and manipulation of such data.

Spectral analysis is often used to determine the qualitative orquantitative composition of a sample. Typical spectral data consist ofthe absorbance of the sample or specimen at different wavelengths orfrequencies of light. Absorbance data are typically plotted againstinverse wavelength (a measure of frequency referred to as wavenumber),with the resulting graph being referred to as a spectrum. Also note thatwhile the discussion of typical usage is appropriately in terms ofabsorbance versus wavenumber, many of the same manipulations areapplicable to a number of other y units (such as %Transmittance,reflectance, Volts) and x units (such as optical retardation of aninterferogram, microns, electron Volts).

In order to interpret spectrum, raw data collected from a sample mayrequire additional manipulations:

(1) Specific sampling techniques affect raw spectral data in known,predictable ways; manipulations can convert the data into asampling-independent standard form.

(2) Sample preparation and sampling techniques may introduce artifacts,and data manipulations may be applied to correct these.

(3) Many samples are mixtures, and manipulations are required todetermine the spectrum and concentrations of the individual compoundspresent.

In order to eliminate known artifacts and eliminate known componentsfrom a sample compound, the data points of the sample spectrum arecommonly modified. In one method, each spectral data point in the samplespectrum S, is modified by a corresponding data point representing aknown sample compound, in the form of a reference spectrum R. Theresulting modified spectrum Z, is related to S and R by equation (1),where a and b are scalar values.

    Z=S-(a*R)+b                                                (1)

Typically, the user inputs a value for "a" and "b" and the processorcalculates the modified spectrum Z. After observing the results of themodified spectrum Z, the user can again modify the values for "a" and"b" and review the new spectrum Z. This process is repeated until theuser is satisfied with the appearance of the modified spectrum Z. Asimilar modification of a sample spectrum is used in determining thecomposition of the sample or is used in adjusting the baseline offset ofthe spectrum.

The user often magnifies portions of the sample spectrum to concentratehis analysis. Current systems allow the user the ability to increase ordecrease the amount of the spectrum, i.e. the range of wave numbers,that is displayed to the user.

SUMMARY OF THE INVENTION

The present invention provides user interface enhancements in acomputerized spectral analysis system that allow the user to directlymanipulate spectral representations on the display in a highly intuitiveand interactive manner. The user is able, with a pointing device, todirectly select a portion of the spectrum for display and to directlyperform graphic manipulation of the spectrum, such as spectralsubtraction.

According to a preferred embodiment of the invention, a method ofdisplaying a spectrum on a computer system having a display and agraphical input device includes the steps of displaying a reduced sizeview of the spectrum in a radar window on the display; displaying anoverlay window on top of the reduced view; displaying a portion of thespectrum corresponding to the portion of the reduced view bounded by theoverlay window in a detailed window on the display; and thereafterdisplaying a resized and/or repositioned overlay window on top of thereduced view in response to input from the graphical input device, theresized and/or repositioned window bounding a second portion of thereduced view; and displaying a second portion of the spectrumcorresponding to the second portion of the reduced view in the detailedwindow on the display.

According to another embodiment of the invention, a method forgraphically manipulating a sample spectrum on a computer system includesthe steps of displaying at least a portion of a difference spectrum onthe display, the difference spectrum being the mathematical differencebetween the sample spectrum and a scaled reference spectrum, the scaledreference spectrum being a reference spectrum scaled by a scaled value;and updating the scaled value in response to graphical manipulation ofthe difference spectrum by the graphical input device.

Further understanding of the nature and advantages of the invention maybe realized by reference to the remaining portions of the specificationand drawings. In the drawings, similarly numbered items represent thesame or functionally equivalent structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a computer system used to execute thepresent invention;

FIG. 2 illustrates one embodiment of the present invention;

FIG. 3A is a flow diagram of one embodiment of the process and result ofutilizing an overlay window in the radar window;

FIG. 3B a flow diagram of another embodiment of the process of utilizingan overlay window in the radar window;

FIG. 3C is a flow diagram of another embodiment of the process ofutilizing an overlay window in the radar window;

FIG. 4A is a flow diagram of an embodiment of the process of displayinga user-selected portion of a spectrum;

FIG. 4B is a flow diagram of another embodiment of the process ofdisplaying a user-selected portion of a spectrum;

FIG. 5A schematically illustrates moving and stretching of the overlaywindow on a full spectrum;

FIG. 5B schematically illustrates the detailed window corresponding tothe overlay window at a first position in FIG. 5A;

FIG. 5C schematically illustrates the detailed window corresponding tothe overlay window at a second position in FIG. 5A;

FIG. 6 illustrates a display of another embodiment of the presentinvention;

FIG. 7 illustrates the display of a portion of a sample spectrum and aportion of a reference spectrum in a detailed window;

FIG. 8 is a flow diagram of an embodiment of the process of forming adifference spectrum;

FIG. 9 illustrates a display of a portion of an initial differencespectrum and portions of two representative difference spectrum;

FIG. 10 illustrates the result of searching the sample spectrum in FIG.2 against a library of known spectrum;

FIGS. 11 and 12 illustrate the definition of a portion of a baselineoffset as a function of wavenumber and the resulting spectrum;

FIG. 13A illustrates a display of a portion of a spectrum on a detailedwindow;

FIG. 13B illustrates the result of an automatic subtraction based upon aregion of interest;

FIG. 14 illustrates retrieving a previously scanned sample spectrum froma disk drive;

FIG. 15 illustrates the peak mode;

FIG. 16 illustrates a document containing a spectral library thatincludes names and index information for the spectrum, the actualspectrum, and properties and structures of the compounds;

FIGS. 17 and 18 illustrates a document containing a collection ofspectrum used to set up and calibrate quantitative analysis;

FIG. 19 illustrates a document containing a processing history;

FIG. 20 illustrates a document containing the results of a spectralsearch;

FIG. 21 is a flow diagram of one embodiment of the process of displayinga user selected set of data from a first and a second spectrum includingspectrum traces in rows of a spreadsheet; and

FIG. 22 is a flow diagram of one embodiment of the process of displayinga user selected set of data from a first and a second spectrum includingspectrum traces at a user selected horizontal range in columns of aspreadsheet.

DESCRIPTION OF THE PREFERRED EMBODIMENT

System Overview

FIG. 1 is a block diagram of a system 1 according to a preferredembodiment of the present invention. System 1 includes a monitor 2, acomputer 3, a keyboard 4, a mouse 5, and a spectrometer 6. Computer 3includes familiar computer components such as a processor 7, and memorystorage devices, such as a random access memory (RAM) 8, a disk drive 9,and a system bus 11 interconnecting the above components. Mouse 5 is butone example of a graphical input device, also known as a pointingdevice, a trackball is another.

In a preferred embodiment, System 1 includes an IBM PC compatiblepersonal computer, running Windows-NT operating system by MicrosoftCorporation and an infra-red spectrometer Model Number FTS 60A fromBio-Rad Laboratories, Inc., and Win-IR Pro software, currently underdevelopment by Bio-Rad Laboratories, Inc.

FIG. 1 is representative of but one type of system for embodying thepresent invention. It will be readily apparent to one of ordinary skillin the art that many system types and configurations are suitable foruse in conjunction with the present invention.

Display Overview

FIG. 2 illustrates the display of one embodiment of the presentinvention, as it would appear on monitor 2. A typical display includes a"radar" window 10 having an overlay window 20, and a detailed window 30.Radar window 10 displays a full range of a spectrum 40, overlay window20 bounds a portion 50 of spectrum 40, and detailed window 30 displaysportion 50 (labeled 51 for convenience). Spectrum 40 is a display ofdata for a sample spectrum, and can be displayed in a user-selectedcolor.

In accordance with standard user interfaces, a menu bar 60, and commandbuttons 70-79 and 61-63 are included on the display to provide functioncapability to the user. In a preferred embodiment of the presentinvention, command button 70 is a scan button; command button 71 is aautomatic vertical scaling button; command button 72 is a new documentbutton; command button 73 is an open folder; command button 74 is a diskselect button; command button 75 is a clipboard button; command button76 is an automatic ranging button; command button 77 is an overlaywindow button; command button 78 is a spectrum mask button; commandbutton 79 is a peak mode button; command button 61 is a graphicsubtraction mode button; command button 62 is a baseline correctionbutton; and command button 63 is a reference definition button.

In a preferred embodiment, the user first selects command button 70, thescan button, or one of commands in menu bar 60 to initiate scanning ofthe sample in spectrometer 6. The spectrometer 6 scans a sample (notshown) and processor 7 stores the absorbance data of the sample atdifferent wave numbers in memory 8. The absorbance data versus the wavenumbers collectively form the sample spectrum. A sample spectrum can beretrieved from disk drive 9 and loaded into memory 8 by selecting acombination of command buttons 73-74.

Once the data are stored in memory 8 from a scan or from disk drive 9,the processor calculates a spectrum that spans a predefined range ofwave numbers or a range of wave numbers having associated absorbancedata. This spectrum is then displayed in radar window 10 on the displayand denoted the spectrum 40.

In the preferred embodiment, absorbance data is plotted on the verticalaxis and wavenumber data is plotted in the horizontal axis.

Next, the processor superimposes overlay window 20 upon radar window 10.The portion of spectrum 40 that is bounded by overlay window 20 definesportion 50. The processor retrieves the spectrum data for portion 50 anddisplays this data labeled portion 51 in detailed window 30 on thedisplay. Since radar window 10, in one embodiment, occupies a smallerportion of the display than detailed window 30, spectrum 40 is alsoreferred to as a reduced view of the spectrum.

Radar Window Manipulation

FIG. 3A is a flow diagram of one embodiment of the process and result ofutilizing an overlay window in the radar window. A reduced view ofspectrum is displayed to the user in the radar window on the display(step 80). The processor generates an initial overlay window in theradar window that bounds and defines a first portion of the spectrum(step 82). The first portion of the spectrum is then displayed to theuser in the detailed window (step 84). Using a graphical input device,such as mouse 5, a user vertically resizes the overlay window in theradar window so that the overlay window bounds and defines a secondportion of the spectrum (step 86). The second portion of the spectrum isthen displayed to the user in the detailed window (step 88).

FIG. 3B is a flow diagram of another embodiment of the process ofutilizing an overlay window in the radar window. In addition to steps80-88 in FIG. 3A, the user may use the graphical input device tohorizontally resize the overlay window in the radar window so that theoverlay window bounds and defines a third portion of the spectrum (step90). In this case, the third portion of the spectrum is then displayedto the user in the detailed window (step 92).

FIG. 3C is a flow diagram of another embodiment of the process ofutilizing an overlay window in the radar window. In addition to steps80-88 in FIG. 3A, the user may use the graphical input device to shiftthe overlay window horizontally and/or vertically in the radar window sothat the overlay window bounds and defines a fourth portion of thespectrum (step 94). In this case, the fourth portion of the spectrum isthen displayed to the user in the detailed window (step 96). In thepreferred embodiment of the present invention, the portion of thespectrum displayed in the detailed window on the display is dynamicallyupdated as the overlay windows are resized and/or repositioned.

FIG. 4A is a flow diagram of an embodiment of the process of displayinga user-selected portion of a spectrum selected in the reduced display. Aspectrum is first displayed to the user on the display (step 98). In thepreferred embodiment of the present invention, the user simultaneouslyselects a range of wave numbers with the graphical input device on thedisplay (step 100) and selects a range of absorbance values also withthe graphical input device on the display (step 102). The user selectsthe respective ranges with the graphical input device, such as mouse 5,using well known techniques such as clicking upon a base value, anddragging mouse 5 until the desired ranges are achieved. Once therespective ranges are defined by the user, a portion of the spectrumcorresponding to the respective ranges is displayed to the user (step104).

FIG. 4B is a flow diagram of another embodiment of the process ofdisplaying a user-selected portion of a spectrum. In addition to thesteps 98-104 in FIG. 4A, the user selects a second range of wave numberson the display (step 106) and the user selects a second range ofabsorbance values on the display (step 108), again using well knowntechniques such as clicking upon a base value, and dragging mouse 5until the desired ranges are achieved. In the preferred embodiment ofthe present invention these steps can occur simultaneously. Once therespective second ranges are defined by the user, a portion of thespectrum corresponding to the respective second ranges is displayed tothe user (step 110).

In a preferred embodiment, in the detailed window, the user can "zoomin" on a portion of spectrum 51 by directly defining a region ofspectrum 51 in detailed window 30 with the graphical input device in thesame manner as overlay window 20. In response, overlay window 20 isupdated to reflect the region of the spectrum displayed in detailedwindow 30.

FIG. 5A illustrates schematically the moving and stretching of overlaywindow 20 from a first position to a second position in radar window 10.The overlay window at the second position is denoted 20". Overlay window20 includes a horizontal side 22 and a vertical side 24, and overlaywindow 20" includes a horizontal side 22" and a vertical side 24".Overlay window 20 bounds portion 50 and overlay window 20" bounds aportion 50" of the spectrum 40.

In a preferred embodiment, the user employs a graphical input devicesuch as a mouse to manipulate overlay window 20 using well known methodssuch as pointing, clicking, and dragging a pointer on the display.Specifically with mouse 5, the user independently varies the horizontallocation, the vertical location, and the size of overlay window 20within radar window 10.

The user, clicking the pointer within overlay window 20 and dragging thepointer in the horizontal and vertical direction within radar window 10,shifts the position of overlay window 20 within radar window 10. Theshift in the overlay window 20 is reflected in detailed window 30 by theprocessor displaying different wavenumber data and absorbance data,although the processor maintains the range of wave numbers (horizontalrange) and the range of absorbance values (vertical range).

The user, clicking the pointer on vertical side 24 and dragging thepointer in the horizontal direction within radar window 10, increases ordecreases the size of horizontal side 22 of overlay window 20 withinradar window 10. The change in size of horizontal side 22 is alsoreflected in detailed window 30 by the processor increasing ordecreasing the range of wave numbers displayed in detailed window 30.Similarly, the user clicking the pointer on horizontal side 22 anddragging the pointer in the vertical direction within radar window 10,increases or decreases the size of vertical side 24 of overlay window 20within radar window 10. The change in size of vertical side 24 is alsoreflected in the detailed window 30 by the processor increasing ordecreasing the range of absorbance values displayed in detailed window30.

FIG. 5B illustrates schematically detailed window 30 corresponding tooverlay window 20 in FIG. 5A. Detailed window 30 includes a horizontalscale 102 representing a range of wave numbers, a vertical scale 104representing a range of absorbance values, and portion 51 of spectrum40.

In operation, overlay window 20 on spectrum 40 defines portion 50 ofspectrum 40. Based upon the size and position of horizontal side 22 andthe size and position of vertical side 24 of FIG. 5A, the processordetermines horizontal scale 102 and vertical scale 104, respectively fordetailed window 30. The processor then displays portion 50, labeled 51for convenience, in detailed window 30.

FIG. 5C illustrates schematically detailed window 30" corresponding tooverlay window 20" in FIG. 5A. Detailed window 30" includes a horizontalscale 102" representing a range of wave numbers, a vertical scale 104"representing a range of absorbance values, and portion 51" of spectrum40.

In a preferred embodiment, the user uses mouse 5 to select overlaywindow 20" in FIG. 5A, to shift overlay window 20 horizontally andvertically, and to resize horizontal side 102 and vertical side 104 tobecome overlay window 20". Overlay window 20" on spectrum 40 definesportion 50" of spectrum 40. Based upon the size and position ofhorizontal side 22" and the size and position of vertical side 24" inFIG. 5A, the processor determines horizontal scale 102" and verticalscale 104", respectively for detailed window 30. The processor thendisplays portion 51", in detailed window 30".

In a preferred embodiment, the user uses mouse 5 to draw a new overlaywindow 20" in FIG. 5A. Overlay window 20" on spectrum 40 defines portion50" of spectrum 40. Based upon the size and position of horizontal side22" and the size and position of vertical side 24" in FIG. 5A, theprocessor determines horizontal scale 102" and vertical scale 104",respectively for detailed window 30. The processor then displays portion51", in detailed window 30".

Radar Window Refinements

FIG. 6 illustrates a display of another embodiment of the presentinvention. The examples in FIGS. 2 and 5A-5C illustrate the use of oneradar window 10 with one detailed window 30 on a display. In a preferredembodiment, however, more than one detailed window is displayed to theuser at the same time on the display, such as detailed window 30 and asecond detailed window 31. Thus, a typical monitor display includesradar window 10 having an overlay window 20 and detailed windows 30 and31. Radar window 10 displays a spectrum 40 and overlay window 20 boundsportion 50 of spectrum 40, detailed window 30 displays a portion ofspectrum 40 labeled 51, and detailed window 31 displays a portion 52 ofa second spectrum (not shown). Spectrum 40 and the second spectrum aredisplays of spectrum data.

Multiple detailed windows such as 30 and 31 are used, for example, whenthe user wants to perform a visual comparison of two or more differentspectrum at the same time. Although it is possible to have as many radarwindows as there are detailed windows on the display, because of thelimited display area on monitor 2, in the preferred embodiment, only oneradar window 10 is provided.

In the preferred embodiment, radar window 10 displays the spectrumassociated with an "active" detailed window and an "active" spectrum.The "active" spectrum is the spectrum upon which the processor canperform operations, such as saving, modifying, etc. To "activate" aspectrum and "activate" a detailed window, the user uses a graphic inputdevice such as mouse 5 and clicks a pointer within one of the detailedwindows on the display. In FIG. 6 the "active" spectrum is spectrum 40and the "active" detailed window is window 30.

The user can override the above described functionality of overlaywindow 20 by selecting command button 71 or command button 76,illustrated in FIG. 2. Selecting command button 71 automaticallyre-scales vertical scale 104 such that the vertical range of portion 51is enhanced, while keeping horizontal scale 102 relatively fixed.Enhancement includes increasing or decreasing the range of absorbancevalues in vertical scale 104.

Selecting command button 76 automatically re-scales vertical scale 104and horizontal scale 102 such that the full range of spectrum 40 isdisplayed in detailed window 30. This includes increasing or decreasingthe range of absorbance values in vertical scale 104 and increasing ordecreasing the range of wave numbers in the horizontal scale 102. Toreturn to utilizing and manipulating overlay window 20 in radar window10, the user selects command button 77.

Graphic Manipulation-Subtraction

Subtraction of a reference spectrum from a sample spectrum allows theuser, for example, to eliminate spectral artifacts from the samplespectrum or to determine the composition of the sample spectrum. Theresult of the spectral subtraction is a difference spectrum.

FIG. 7 illustrates the display of portion 120 of a sample spectrum and aportion 130 of a reference spectrum over the same wavenumber range ondetailed window 30. These portions 120 and 130 can be displayed in twodifferent user selected colors to avoid any confusion between thespectra. The wavenumber ranges of the two spectrum are determined byoverlay window 20 in radar box 10. Portion 120 includes points 122, 124,126, and portion 130, includes points 132, 134, and 136. The referencespectrum includes spectral data from known reference materials such aspure compounds and mixtures.

In a preferred embodiment, the user scans a sample spectrum usingspectrometer 6 (or retrieves a previously scanned spectrum from diskdrive 9) and then selects command button 61 to enter the graphicsubtraction mode. Once in the graphic subtraction mode, the userretrieves a reference spectrum from disk drive 9.

Using overlay window 20 in radar window 10 to survey the sample spectrumand the reference spectrum, the user typically determines which portionsof the sample spectrum and the reference spectrum appear similar inshape. If the sample spectrum does not have waveform characteristicssimilar to that of the reference spectrum, the user may decide to skipthis reference spectrum and load a new reference spectrum from diskdrive 9. If the sample spectrum has similar characteristics to thereference spectrum, the user may decide to perform the graphicalsubtraction. In the example in FIG. 7, the sample spectrum includesregions surrounding points 122 and 124 which are similar in shape toregions surrounding points 132 and 134 of the reference spectrum,respectively.

Once the user determines a reference spectrum to use for the graphicalsubtraction, the processor generates a difference spectrum between thetwo spectrum. The difference spectrum can be displayed in a third userselected color to visually distinguish the difference spectrum from theother spectra.

FIG. 8 is a flow diagram of an embodiment of the process of forming adifference spectrum. At least a portion of an initial differencespectrum is first displayed to the user on the display (step 140). Inone embodiment, the initial difference spectrum is equal to the samplespectrum, i.e., the values of "a" and "b" in equation (1) are zero (0).Alternatively, the initial difference spectrum can be proportional orlinearly related to the sample spectrum. The user selects a point on theinitial difference spectrum with a pointing device, such as mouse 5(step 142). The selected point represents a data point in the initialdifference spectrum having an absorbance value at an associated wavenumber. The user moves the point from the original position to a newposition, again using mouse 5 in a well known manner (step 144). Theprocessor then determines the vertical offset between the originalposition and the new position (step 146). In the preferred embodimentthe difference in absorbance values between the original position to thenew position is represented by the vertical offset.

A scaling factor for the reference spectrum is determined based upon thevalue of the vertical offset and upon the value of the referencespectrum at the wavenumber of the selected point (step 148). In oneembodiment, the scaling factor is the difference in absorbance valuesdivided by the absorbance value of the reference spectrum at the wavenumber. The reference spectrum is then uniformly scaled by the scalingfactor to form a scaled reference spectrum (step 150).

In one embodiment, the absorbance value for each data point in thereference spectrum is multiplied by the scaling factor to form thescaled reference spectrum. The processor then determines the differencebetween the sample spectrum and the scaled reference spectrum (step152). In one embodiment, for each wave number, the absorbance value forthe sample spectrum is subtracted by the absorbance value for the scaledreference spectrum to form the difference spectrum. At least a portionof the resulting difference spectrum is then displayed to the user (step154), and the resulting difference spectrum will run through the newposition of the selected point. The display of the difference spectrum,in a preferred embodiment, serves as immediate feedback to the user ofthe results of the subtraction process. The user may repeatedly performsteps 140-154 using the difference spectrum in place of the samplespectrum, to rescale and resubtract the reference spectrum from thedifference spectrum and to form a new difference spectrum.

In some situations, the reference spectrum or the sample spectrumcontain a baseline offset. When performing the above described steps,when the reference spectrum is scaled, the scaled reference spectrumalso contains a baseline offset. Subtracting the scaled referencespectrum from the sample spectrum would then result in a differencespectrum having a non-zero baseline offset. Although a non-zero baselineoffset does not interfere with qualitative results of the subtraction,the offset of the sample spectrum may be visually distracting to theuser. To address this issue, in a preferred embodiment of the presentinvention, when the scaling factor "a" is determined, the offset factor"b" is also determined such that for each difference spectrum, thebaseline offset will be approximately zero.

FIG. 9 illustrates a display of a portion 160 of an initial differencespectrum (not shown in its entirety) and portions 160, 160', and 160" ofthree representative difference spectra (not shown in their entirety) ona detailed window 31'. Portion 160 includes points 162, 164, 166,portion 160' includes points 162', 164', and 166', and portion 160"includes points 162", 164", and 166".

In a preferred embodiment, the initial difference spectrum is set equalto the sample spectrum. The initial difference spectrum is equal to thesample spectrum without the reference spectrum being subtracted. Tocalculate a new difference spectrum the user uses mouse 5 to select apoint on the initial difference spectrum. The user then moves that pointvertically on the display. Moving the point on the initial differencespectrum vertically is equivalent to subtracting a scaled percentage ofthe reference spectrum from the sample spectrum.

Portion 160 illustrates an initial difference spectrum. When a userselects and drags point 162 to point 162', for example, Portion 160 iserased and portion 160' is displayed to the user. Of course multipleintermediate difference spectra are also displayed to the user as theuser moves from 162 to 162'. These are not shown, for clarity. The usercontinues dragging data points until the user is satisfied with thedifference spectrum, for example, 160".

FIG. 9 illustrates the result of the user dragging point 162 of portion160 to point 162' and onto point 162". In a preferred embodiment, onlyone difference spectrum is displayed to the user at a time, e.g., 160,160', or 160". In response to the vertical offset between point 162 to162' and onto 162", the processor calculates the remaining points in thedifference spectrum, as illustrated by portion 160' and 160". In apreferred embodiment, if the baseline offset of the reference spectrumis zero, the baseline compensation factor "b", in equation (1), is setto zero. Equation (1) then simplifies to equation (2).

    Z=S-(a*R)                                                  (2)

In equation (2), Z represents the difference spectrum, S represents thesample spectrum, R represents the reference spectrum, and "a" is thescaling factor for the reference spectrum. In FIGS. 7 and 9, the valueof point 162' corresponds to Z, the point 162 corresponds to S, andpoint 132 corresponds to R for a given wave number. Since the processorknows the values for Z, S, and R, the processor calculates acorresponding value for "a" based upon point 122'. Using this value for"a" and knowing the values of the sample spectrum S and referencespectrum R for the remaining wave numbers, the processor then calculatesthe remaining values for the difference spectrum Z for all the remainingwave numbers.

In FIG. 7, for example, point 122 has an absorbance of about 0.132 andpoint 132 has an absorbance of about 0.137, and in FIG. 9, point 162'has an absorbance of about 0.102. Using equation (2) with Z=0.102,S=0.132, and R=0.137, the scaling factor "a" is calculated to be about0.219.

Using 0.219 for "a" in equation (2), the processor then calculates thedifference spectrum for each of the remaining points from the samplespectrum. For example in FIG. 7, point 124 has an absorbance of about0.119 and point 134 has an absorbance of about 0.125. Using equation (2)with S=0.119, "a"=0.219 as calculated above, and R=0.125, the value ofpoint 164' is calculated to be about 0.916. Point 164' in FIG. 9 is thusset to 0.916. In a preferred embodiment, the described sequentialoperations appear continuous.

In a preferred embodiment, the user graphically manipulates points uponthe difference spectrum, until satisfied that difference spectrum doesnot include any contributions from the reference spectrum. Asillustrated in FIG. 9, by maintaining a baseline offset for thedifference spectrum that is approximately zero, once the absorbance ofthe difference spectrum has reached a relatively constant value, theuser can then identify peaks such as point 166". Point 166" mayrepresent another chemical component in the sample spectrum, forexample.

The difference spectrum can be displayed and manipulated in its ownwindow. The sample spectrum and the reference spectrum may or may not bedisplayed to the user, and if so may be displayed in another window. Forexample, the difference spectrum and the sample spectrum may bedisplayed in windows 31 and 30, respectively, as in FIG. 6.Alternatively, all three spectrum can be displayed in a single window.

The user repeats the above graphic subtraction procedure with a newreference spectrum from a library of reference spectra in order toidentify any remaining components or to remove other artifacts on thedifference spectrum.

Spectral Searching

FIG. 10 illustrates the result of searching the sample spectrum in FIG.2 against a library of known spectrum. The results, stored in componentbox 170 are displayed to the user and can be saved to memory. In apreferred embodiment, component box 170 includes a name column 172, aspectrum column 174, and a structure column 176. Other informationrelated to the spectral information contained in each row may be storedin other columns.

In the preferred embodiment, the processor automatically compares thesample spectrum to a library of reference spectra stored in disk drive 9to determine the composition of the sample spectrum. The processordetermines the composition according to well known algorithms known toone skilled in the art.

In a preferred embodiment, after determining the composition of thesample spectrum, the processor displays the name of the referencesamples matched, a full scale view of the reference spectrum, anddisplays the chemical structure. In FIG. 10, the samples are stored inname column 172, the reference spectrum for the chemicals are shown inspectrum column 174, and the structure of the chemicals are shown instructure column 176.

Graphic Manipulation--Baseline Offset Correction

Baseline Offsets are used to compensate for offsets in absorbance valuesdue to artifacts during collection of the sample spectrum or due toartifacts in subtracting reference spectrum. If an offset is relativelyconstant throughout the range of wave numbers of the sample spectrum,the value of "b" in equation (1) can be set to a constant to correct theoffset. However, if an offset is non-uniform throughout the range ofwave numbers of the sample spectrum, the user can define a baselineoffset as a function of wavenumber to correct the offset. Whencorrecting only the baseline offset, the value of "a" in equation (1) ispreferably set to zero and the value of "b" is modified.

In a preferred embodiment the user directly sets the value of "b" inequation (1) to a constant in two ways. First, when in graphicsubtraction mode, the user can directly select a value for "b" bycommonly used techniques such as entering text in a dialog box, orscrolling through a list of values of "b" with up and down arrows on thedisplay (while "a" is held constant). Second, when in a baselinecorrection mode, the user can graphically set the value of "b" to aconstant. The user enters the baseline correction mode by selectingcommand button 62.

FIGS. 11 and 12 illustrate the definition of a portion of a baselineoffset (not shown) as a function of wavenumber and the resultingspectrum. The baseline offset includes line segments 180 and 182 andcurved segment 184.

In a preferred embodiment, the user directly sets the value of "b" inequation (1) as a function of wavenumber while in the base linecorrection mode. In operation, the user graphically defines the shape ofthe baseline offset in relation to the wavenumber with mouse 5. Usingwell known graphic manipulation techniques from computer drawingprograms, the user can define line or curved segments by defining theappropriate parameters as shown as line segments 180 and 182 and ascurved segment 184. In a preferred embodiment, immediately after editingthe graphic baseline offset, the sample spectrum is updated to reflectthe new baseline offset. This is illustrated in FIG. 12 with thebaseline correction of FIG. 11 of the sample spectrum in FIG. 2.

Graphic Manipulation Based upon Regions of Interest

Regions of Interest (ROI) are areas in a spectrum upon which theprocessor utilizes spectrum data for operations.

FIG. 13A illustrates a display of a portion 190 of a spectrum ondetailed window 30. Portion 190 is a portion of the difference spectrumincluding a region of interest (RO) 200.

In operation, selecting command button 78 in FIG. 2 allows the user todefine an ROI. The user defines an ROI by first delineating a wavenumberrange of the spectrum and choosing whether the delineated range is theROI, or the spectrum outside the delineated range is the ROI.

In a preferred embodiment, without an ROI 200, spectral searching of asample spectrum and a reference spectra is calculated based upon theentire range of wave numbers as illustrated in FIG. 11. In a preferredembodiment, with an ROI 200, spectral searching is calculated based onlyupon the range of wave numbers in the defined ROI 200. The spectralsearching occurs over the entire wavenumber range as without ROI 200,however, ROI 200 is the only region from which the processor analyzesdata. An application where an ROI is used is when the composition ofonly a certain portion of the sample spectrum is of interest.

FIG. 13B illustrates the result of an spectral searching based upon ROI200. In contrast to the result of the spectral searching in FIG. 10, thespectral searching in FIG. 13B results in locating only a particularsubstance.

Other Features

FIG. 14 illustrates retrieving a previously scanned sample spectrum fromdisk drive 9. A dialog box 200 includes a file box 210 a text entry box220, a preview box 230, and a retrieve button 240.

In a preferred embodiment, the user selects buttons 73 or 74 to opendialog box 200 on display 2. The list of files, directories and drives,either local or on a network accessible machine, is displayed in filebox 210. The user selects a file to retrieve from the list of files infile box 210 by using a graphical input device, such as mouse 5, andpointing and clicking upon the file name. Alternatively, the userselects a file to retrieve by typing a file name into keyboard 4, afterfirst selecting text entry box 220 with mouse 5. A preview of the userselected file is displayed in preview box 230 when the user clicks uponthe file name, or enters a file name into text entry box 220. Once theuser is satisfied with the file selection, the user retrieves thespectrum data by pointing and double clicking upon the file name withmouse 5, or clicking upon retrieve button 240.

In a preferred embodiment, a file (or document) contains data (aspectrum) for a sample or a reference, or a series of spectra, orspectra from different samples, or spectra processed in different ways,plus other information related to the spectrum. This typically includesdata from an experiment, an individual's work, a series of relatedexperiments, a day's worth of work, a project, etc.

The presentation of the document by the software is in one window. Amoveable "window shade" lines separates the window into two portions:one containing a large area for the presentation of spectra and thesecond containing a "spreadsheet". This "spreadsheet" format for thedata provides a environment familiar to the user for presenting data tothe user. Each row in the spreadsheet contains cells displayinginformation related to a single spectrum, possibly including but notlimited to properties such as the name of the spectrum, the spectrumtrace itself, text information about the sample or spectrum, thechemical structure of the material, etc. Each column of the spreadsheetis dedicated to a particular spectrum property. The selection ofspreadsheet columns is user configurable.

To modify or view a document, the user is given the ability tomanipulate the data in a manner similar to spreadsheets. A typicaldisplay of a document displays the names of the spectra/traces in onecolumn of the document, the actual spectra/traces in another column ofthe document, the properties of the underlying samples in another columnof the document and other graphic information in yet another column ofthe document. One example of a view of a document is illustrated in FIG.10. Graphic information includes chemical structures as illustrated incolumn 176 of FIG. 10.

FIG. 21 is a flow diagram of one embodiment of the process of displayinga user selected set of data from a first and a second spectrum includingspectrum traces in rows of a spreadsheet. Initially the user retrievinga plurality of data related to a first spectrum and a plurality of datasecond spectrum from the plurality of spectra from the memory (step300). This data is typically stored in the same file. In the next step,a user selected set of data from the plurality of data related to thefirst spectrum, that includes a spectrum trace for the first spectrum,is displayed on the display (step 310). As illustrated in the examplesbelow, the data is displayed in a first row of a "spreadsheet" on thedisplay. Then, a user selected set of data from the plurality of datarelated to the second spectrum, that includes a spectrum trace for thesecond spectrum, is displayed on the display (step 320). The data isdisplayed in a second row of the "spreadsheet" on the display.

The interface allows the user to access individual spectra/traces,ranges or particular spectra/traces, or groups of spectra/traces in adocument or between documents, and allows the user to align or registerspectra that span different ranges. The interface also allows the userto choose which columns of a document to display at any one time. Such achoice is variable between documents and between applications.

The ability to align spectra/traces is important where a series oftraces are displayed in a spreadsheet column having corresponding datapoints (e.g. wavenumber) in the traces, whether the spectra have commonrange or not. In one embodiment, all spectra in a spreadsheet withcommon X axis units are displayed each scaled separately to display itsfull extent. In another embodiment, all spectra having a common range ofwavenumbers, for example, are displayed using the same display rangelimits and same range scale. Selecting a spectrum by clicking in thespectrum's trace display cell causes that spectrum to be shown with thefull extent of its data range, and causes all other spectra displayed inthat specific spreadsheet view that share X units with the selectedspectrum to also be displayed with that same extent. In an alternativeembodiment, the displays of spectra are rescaled to the extent requiredto show the full x range of all spectrum sharing common X units.

FIG. 22 is a flow diagram of one embodiment of the process of displayinga user selected set of data from a first and a second spectrum includingspectrum traces at a user selected horizontal range in columns of aspreadsheet. In addition to the steps illustrated in FIG. 21, thespectrum trace for the first spectrum is displayed at a user selectedhorizontal range in a column of the spreadsheet on the display (step340) and the spectrum trace for the second spectrum is displayed at theuser selected horizontal range in the column of the spreadsheet on thedisplay (step 350).

Examples of the information stored in documents include:

1) A document containing a spectral library that includes names andindex information for the spectrum, the actual spectrum, and propertiesand structures of the compounds. This is illustrated in FIG. 16.

2) A document containing a collection of spectrum used to set up andcalibrate quantitative analysis. For example, a document that containsthe actual spectrum of the specimens, the names of the componentspresent in each specimen, the concentrations of those components in eachspecimen, the portion(s) of the spectrum to be used in the calibrationand analysis, the style of analysis (e.g. band height measurement,partial least squares analysis), and the resulting calibration data.This is illustrated in FIG. 17 and FIG. 18.

3) A document containing a collection of spectrum to be analyzed. Forexample, a document that contains spectrum to be analyzed, the resultingcomponents and component concentration present in each spectrum, themethod used for the analysis, and the processing history. This isillustrated in FIG. 19.

4) A document containing a set of spectrum from an infrared mappingexperiment. For example, spectrum that are associated with coordinatesfrom which the spectrum was obtained, and data obtained from the set ofspectrum that produce infrared-based maps of the specimen.

5) A document containing a set of spectrum collected under varyingconditions. For example, different experimental conditions and theassociated data. Conditions include those internal to the spectrometer(e.g. resolution, number of scans), and external to the spectrometer(e.g. temperature of the specimen, pressure). Alternatively, thesoftware may itself control those conditions.

FIG. 20 illustrates a document containing both the results of a spectralsearch as well as the sample spectrum.

FIG. 15 illustrates the peak mode. As will be described below, the peakmode allows the user to quickly obtain characteristics of a selectedpeak.

In a preferred embodiment, selecting command button 79 in FIG. 2 entersthe system into a "peak" mode. In peak mode the user uses mouse 5 toselect a point such as point 53 on partial spectrum 51. In response tothe selection, the processor automatically determines characteristics ofthe closest peak, such as peak 54. These characteristics can include themaximum and minimum absorptions of the peak, the wavenumber of the peak,the area of the peak, the range of wave numbers for the peak.

Conclusion

In the foregoing specification, the invention has been described withreference to a specific exemplary embodiments thereof. Many changes ormodifications are readily envisioned. For example, changing thegraphical manipulation from that of equation (1), changing the effect ofthe graphical manipulation based upon direction of movement, andincluding further functional buttons on the display, among otherchanges, are included within other embodiments of the present invention.

The specification and drawings are, accordingly, to be regarded in anillustrative rather than in a restrictive sense. It will, however, beevident that various modifications and changes may be made thereuntowithout departing from the broader spirit and scope of the invention asset forth in the claims.

What is claimed is:
 1. A method of displaying a plurality of datarelated to a plurality of spectra on a computer system, the computersystem including a display and a memory, the method comprising the stepsof:retrieving a plurality of data related to a first spectrum and aplurality of data related to a second spectrum from the plurality ofspectra from the memory; displaying a user-selected set of data from theplurality of data related to the first spectrum including a spectrumtrace for the first spectrum, in a first row of a spreadsheet on thedisplay; displaying a user-selected set of data from the plurality ofdata related to the second spectra including a spectrum trace for thesecond spectrum, in a second row of the spreadsheet on the display. 2.The method of claim 1,wherein the first spectrum displaying step furthercomprises the step of displaying the spectrum trace for the firstspectrum at a user-selected horizontal range in a column of thespreadsheet on the display; and wherein the second spectrum displayingstep further comprises the step of displaying the spectrum trace for thesecond spectrum at the user-selected horizontal range in the column ofthe spreadsheet on the display.
 3. The method of claim 2,wherein thefirst spectrum displaying step further comprises the step of displayingthe spectrum trace for the first spectrum at a user-selected horizontalscale; and wherein the second spectrum displaying step further comprisesthe step of displaying the spectrum trace for the second spectrum at theuser-selected horizontal scale.
 4. The method of claim 1,wherein thefirst spectrum displaying step further comprises the step of displayinga full range of the spectrum trace for the first spectrum in a column ofthe spreadsheet on the display; and wherein the second spectrumdisplaying step further comprises the step of displaying a full range ofthe spectrum trace for the second spectrum in the column of thespreadsheet on the display.
 5. The method of claim 1,wherein the firstspectrum displaying step further comprises the step of displaying atleast a portion of the spectrum trace for the first spectrum in a columnof the spreadsheet on the display; and wherein the second spectrumdisplaying step further comprises the step of displaying at least aportion of the spectrum trace for the second spectrum in the column ofthe spreadsheet on the display, wavenumbers of the portion of thespectrum trace for the second spectrum aligned with wavenumbers of theportion of the spectrum trace for the first spectrum.
 6. An apparatusfor displaying a plurality of data related to a plurality of spectra ona computer system, the computer system including a memory, the apparatusfurther comprising:a processor for retrieving a plurality of datarelated to a first spectrum and a plurality of data related to a secondspectrum from the plurality of spectra from the memory; a displayconfigured to display a user-selected set of data from the plurality ofdata related to the first spectrum including a spectrum trace for thefirst spectrum, in a first row of a spreadsheet, and configured todisplay a user-selected set of data from the plurality of data relatedto the second spectra including a spectrum trace for the secondspectrum, in a second row of the spreadsheet.
 7. The apparatus of claim6,wherein the display is also configured to display the spectrum tracefor the first spectrum at a user-selected horizontal range in a columnof the spreadsheet; and wherein the display is also configured todisplay the spectrum trace for the second spectrum at the user-selectedhorizontal range in the column of the spreadsheet.
 8. The apparatus ofclaim 6,wherein the display is also configured to display the spectrumtrace for the first spectrum at a user selected horizontal scale; andwherein the display is also configured to display the spectrum trace forthe second spectrum at the user selected horizontal scale.
 9. Theapparatus of claim 6,wherein the display is also configured to display afull range of the spectrum trace for the first spectrum in a column ofthe spreadsheet on the display; and wherein the display is alsoconfigured to display a full range of the spectrum trace for the secondspectrum in the column of the spreadsheet on the display.
 10. Theapparatus of claim 6,wherein the display is also configured to displayat least a portion of the spectrum trace for the first spectrum in acolumn of the spreadsheet on the display; and wherein the display isalso configured to display at least a portion of the spectrum trace forthe second spectrum in the column of the spreadsheet on the display,wavenumbers of the portion of the spectrum trace for the second spectrumaligned with wavenumbers of the portion of the spectrum trace for thefirst spectrum.
 11. A computer system for displaying a plurality of datarelated to a plurality of spectra on a computer system, the computersystem including a display, the computer system further comprising:amemory storage device including:code that directs a processor toretrieve a plurality of data related to a first spectrum and a pluralityof data related to a second spectrum from the plurality of spectra; codethat directs the display to display a user-selected set of data from theplurality of data related to the first spectrum including a spectrumtrace for the first spectrum, in a first row of a spreadsheet; and codethat directs the display to display a user-selected set of data from theplurality of data related to the second spectra including a spectrumtrace for the second spectrum, in a second row of the spreadsheet. 12.The apparatus of claim 11, wherein the memory storage device alsoincludes:code that directs the display to display the spectrum trace forthe first spectrum at a user-selected horizontal range in a column ofthe spreadsheet; and code that directs the display to display thespectrum trace for the second spectrum at the user-selected horizontalrange in the column of the spreadsheet.
 13. The apparatus of claim 11,wherein the memory storage device also includes:code that directs thedisplay to display the spectrum trace for the first spectrum at a userselected horizontal scale; and code that directs the display to displaythe spectrum trace for the second spectrum at the user selectedhorizontal scale.
 14. The apparatus of claim 31, wherein the memorystorage device also includes:code that directs the display to display afull range of the spectrum trace for the first spectrum in a column ofthe spreadsheet on the display; and code that directs the display todisplay a full range of the spectrum trace for the second spectrum inthe column of the spreadsheet on the display.
 15. The apparatus of claim11, wherein the memory storage device also includes:code that directsthe display to display at least a portion of the spectrum trace for thefirst spectrum in a column of the spreadsheet on the display; and codethat directs the display to display at least a portion of the spectrumtrace for the second spectrum in the column of the spreadsheet on thedisplay, wavenumbers of the portion of the spectrum trace for the secondspectrum aligned with wavenumbers of the portion of the spectrum tracefor the first spectrum.
 16. A method for displaying data associated witha spectrum on a computer system, the computer system including a displayand a memory, the method comprising the steps of:retrieving a firstplurality of data associated with the spectrum and a second plurality ofdata associated with the spectrum from the memory; displaying a firstset of data from the first plurality of data, including a first spectrumtrace, in a first row and a column of a spreadsheet on the display; anddisplaying a second set of data from the second plurality of data,including a second spectrum trace, in a second row and the column of thespreadsheet on the display.
 17. A computer program product fordisplaying data related to spectra on a computer system, the computerprogram product comprising:a memory storage device including:code thatdirects a processor to retrieve data related to a first spectrum anddata related to a second spectrum from the spectra; code that directs adisplay to display a user-selected set of data from the data related tothe first spectrum including a spectrum trace for the first spectrum, ina first row of a spreadsheet; and code that directs the display todisplay a user-selected set of data from the data related to the secondspectrum including a spectrum trace for the second spectrum, in a secondrow of the spreadsheet.
 18. The computer program product of claim 17,wherein the memory storage device also includes:code that directs thedisplay to display the spectrum trace for the first spectrum at auser-selected horizontal range in a column of the spreadsheet; and codethat directs the display to display the spectrum trace for the secondspectrum at the user-selected horizontal range in the column of thespreadsheet.
 19. The computer program product of claim 17, wherein thememory storage device also includes:code that directs the display todisplay the spectrum trace for the first spectrum at a user selectedhorizontal scale; and code that directs the display to display thespectrum trace for the second spectrum at the user selected horizontalscale.
 20. The computer program product of claim 17, wherein the memorystorage device also includes:code that directs the display to display afull range of the spectrum trace for the first spectrum in a column ofthe spreadsheet on the display; and code that directs the display todisplay a full range of the spectrum trace for the second spectrum inthe column of the spreadsheet on the display.
 21. The computer programproduct of claim 17, wherein the memory storage device alsoincludes:code that directs the display to display at least a portion ofthe spectrum trace for the first spectrum in a column of the spreadsheeton the display; and code that directs the display to display at least aportion of the spectrum trace for the second spectrum in the column ofthe spreadsheet on the display, wavenumbers of the portion of thespectrum trace for the second spectrum aligned with wavenumbers of theportion of the spectrum trace for the first spectrum.